This application requests support for the next wave of a long- term ongoing, longitudinal study . This longitudinal study examines the etiologic determinants of changes between adolescence and young adulthood in tobacco use and problem behaviors, and the consequences of tobacco use on the individual's functioning . The sample includes 444 disadvantaged inner-city African-American and Puerto Rican young adults who were seen in early/middle adolescence, and then in late adolescence. A third data collection is proposed to accomplish the following: (1) to examine the interrelations and interactions of risk and protective factors, including personality, family, peers, ecological context, acculturation/cultural values, and African American and Puerto Rican ethnic identification, as they affect the course of tobacco use (i.e.,stability,change), illegal drug use, and delinquency in these young adults; and (2) to study the consequences of early tobacco use on young adult intra- and interpersonal functioning. Individual interviews with the young adult subjects will be conducted by trained ethnically matched interviewers. Scales with adequate psychometric properties measuring the independent variables will be developed from the interview schedules. The primary analytic techniques will be LISREL, hierarchical regression analysis, and regression analysis and Latent Growth Modeling. The significance of this study lies in its longitudinal design with intrapersonal, interpersonal and problem behavior data available in depth on young adult , inner-city African-Americans and Puerto Ricans . This is the first time such longitudinal data will be available for a sample in this age group at particular risk for tobacco use. Knowledge of the protective factors which help offset the risks for tobacco use and knowledge of the consequences of tobacco use for psychosocial functioning are important for determining the foci and timing of effective prevention and treatment programs.